This invention relates to a vinyl chloride resin composition made both low in density and delustered and having a superior abrasion resistance and a good microballoon-retainability, and molded products using the same such as steering wheel.
Vinyl chloride resins have superior physical and chemical properties and molding processability and are relatively cheap, and hence have been broadly used for various applications. However, vinyl cloride resins have specific gravities as high as 1.41 and even soft vinyl chloride resins obtained by blending a plasticizer therewith usually have specific gravities of 1.2.about.1.4. Thus the resins have a serious drawback that they are much heavier than general-purpose synthetic resins, for example, heavier by 30.about.60% than polypropylene and by 200.about.250% than foamed polyurethane. Further, vinyl chloride resins have other drawbacks in that molded products of vinyl chloride resins have an intense surface luster so that they cause a cheap feeling, and their hand feeling is bad (a sticky feeling).
As to the process for making vinyl chloride resins lightweight, foaming processes have been employed, but they have associated therewith various problems such as the molding cycle is long, the product yield is inferior, their reuse is impossible, etc.; hence they have not yet been fully satisfactory.
As to making low density and low luster vinyl chloride resins, the present inventors found that a composition having microballoons and a plasticizer blended with a copolymer of vinyl chloride with polyethylene glycol diacrylate or polyethylene glycol dimethacrylate has superior properties, and applied for patent (Japanese Patent Application No. Sho 58-74500/1983). However, as the amount of microballons blended in the above composition increased, there occurred a phenomenon that microballoons exposed on the surface of molded products slipped off due to abrasion to reduce the commodity value of the molded products. Particularly when such a low density composition was used as a covering layer on steering wheels of autocars, etc., a problem of slipping off of the microballoons due to abrasion was raised, and further vinyl chloride resins having a large amount of such a filler blended therein are liable to have reduced mechanical strength, and also peeling off of the covering layer from the metal core of steering wheels as well as collapse of the covering layer are liable to occur. Thus these drawbacks have constituted a most serious obstacle to the attempt of making vinyl chloride resins lightweight by increasing the amount of microballoons blended.
The present inventors have made extensive research in order to overcome the above problems of vinyl chloride resin compositions using microballoons. As a result we have found that the aimed object can be achieved by blending polyvinyl acetate with the vinyl chloride resin composition.